Former President George W. Bush came to South Carolina not just to praise his brother former Florida Gov. Jeb Bush, but also to bury Republican front-runner Donald Trump.

The Bush brothers held their first joint rally of the 2016 campaign. Despite early fundraising success, Jeb Bush has struggled to gain traction with voters, finishing fourth in New Hampshire and sixth in Iowa.

But Trump went beyond his usual riffs against his "low energy" primary opponent in the Republican debate Saturday night to hit the ex-president's legacy on Iraq and even the 9/11 terrorist attacks, once sacrosanct in GOP circles.

"I don't know about you," said South Carolina Sen. Lindsey Graham, himself a former 2016 GOP presidential candidate. "But I like Bushes!"

So, traditionally, has South Carolina. George H.W. Bush beat Bob Dole in their Republican primary in 1988 while George W. triumphed over John McCain in 2000, with both wins coming at crucial times for their successful presidential campaigns.

George W. Bush praised the state in his folksy remarks, saying "even a steaming pile of manure" couldn't ruin the bacon at a local restaurant. He joked that wife Laura, also on hand for the rally, called their life after the White House "the afterlife."

"We miss our friends," he said. "But we don't miss power and fame."

But the former president took many thinly veiled shots at Trump. He praised his brother for having a "faith that reveals itself in good works, not loud words." While Bush 43 quipped that voters should pick the candidate "who's got the most opinionated mother," a reference to former First Lady Barbara Bush, he expressed an opinion about what kind of candidate they should avoid too.

"We do not need someone in the Oval Office who mirrors and inflames our anger and frustration," he said.

The former president also talked about his memories of 9/11, an indirect rebuke of Trump. "I became a president no president should have to be," he said.

In the aftermath of the terrorist attacks, George W. Bush bonded with conservatives in a way that his father never did and his brother has been unable to replicate during his presidential campaign.

What George W. implied, Jeb made explicit when it was his turn to speak. The Floridian called Trump's criticism of his brother "strange," adding, "I thought it was Michael Moore on the stage."

Trump has seen a lot of comparisons to Moore, Code Pink and other left-wing voices after he accused the former president of lying about Iraq's weapons of mass destruction and failing to keep the country safe on 9/11. The billionaire has made similar comments before without seeing his standing among Republican primary voters diminish, but ahead of the voting in military-friendly South Carolina, his GOP detractors think this could be a promising line of criticism.

Trump has led in polls of South Carolina primary voters, but most of the polling predates Saturday night's debate. Jeb Bush is hoping to get his campaign back on track in the South's first primary.